Insulation board and method of making the same



Sept. 3, 1940. s. J. KELLEY INSULATION BOARD AND METHOD OF MAKING THESAME Filed July 28. 1934 Patented Sept. 3, 1940 UNITED STATES PATENT or-"lca INSULATION BOARD AND METHOD. OF

- MAKING THE SAME of Pennsylvania Application July 28, 1934, Serial No.737,331

'16 Claims. (01. 154-8) This application is a continuation in part of mycopending application Serial No. 652,800, filed January 21, 1933 andentitled Building board.

My invention relates to an insulation board and method of making thesame and more particularly to an insulation board which is structurallystrong, has high resistance to bending stress, is light in weight andpossesses good insulating properties, and to a method for economicallyand 10 efllciently manufacturing the same.

It has been common practice in the wall board industry, and particularlyin the so-called gypsum boards, to lower the weight and increase theheat insulating value by incorporating sawdust or other light woodymaterial into the body of the board. It is obvious that the structure isnot an eflicient heat insulator for the insulation value of a productdepends upon its ability to prevent the transmission of heattherethrough, and since the major constituent of such boards is gypsum,which is a relatively good heat conductor, and since the board is notrendered sufllciently open and porous by reason of the incorporation ofthe woody filler to materially affect such transmission of heat, theinsulating value of such product marily to the relatively largeproportion of void.

space to fibers, with the void spaces being so small as to preventthesetting up of convection currents within the board. Dead .air isgenerally considered to be one of the best heat insulators.

The gypsum type wall board has found a definite place in the buildingarts due to its rigidity and strength and because of its smooth surfacewhich permits decoration and which may be utilizedas a plaster base ifdesired. These gypsum boards, however, have been to some extent replacedby the fibrous insulation boards because of theirinsulating qualities.On the other hand, fibrous insulation boards generally are deficient inthat theyjare not structurallyas strong as gypsum boards, are' notsmooth surfaced, are not adapted to receive the decorative treatment ofgypsum boards and are not fire resistant. Furthermore,one of the majorproblems incident to the use of flber boards,'which is not encounteredin gypsum boards, is to prevent buckling upon the absorption of moistureand, if finished, crackingupon contraction by reason of giving upmoisture. It is well known that the fiber boards 5 now on the marketwill absorb about 5 per cent and some as much as 35 per cent of theirown volume of moisture and dimensional changes upon such absorptionrange as high as 2 to 3 per cent of linear expansion. It will beapparent, therefore, that the fiber boards of commerce 5 which possesshigh insulating value because of their low density and high percentageof occluded air space are unsuited for many usesbecause of their lack ofstructural strength and rigidity, their roughened surface, theirsuscep-. 1o

tomaceous earth and does not provide the proper so pore structure, andfor that reason, material of this sort has not been commerciallyexploited. It has also been proposed to overcome the inherent defects offiber boards by cementing to the faces of the boards, by means of-asodium'silicat'e ce- 26 ment, preformed sheets of asbestosfiber-hydraulic cement composition. This laminated product possesses a.relatively high degree of resistance to'deformation and structuralstrength but is ex-, pensive to produce and has a tendency to beso comeloose upon contact with moisture, and permits expansion of the fiberboard which it covers. There is no mechanical bond between thelaminations.

It is an object of my invention to produce an 35 insulation board whichis structurally strong and rigid and possesses a high insulating value,a low specific weight andpresents a smooth surface for decoration. It isa further object of my invention to provide an insulation board in whichn the insulating core is so sheathed and confined that expansion thereofupon the absorption of moisture is restricted and the board is renderedfire resistant. My invention further contem plates a method foreconomically manufacturing 45 such insulation board by forming a stripof indefinite length and cutting to' the desired board size, whereby thematerial may be economically manufactured by a continuous process.

Any of the well known fibrous insulation 5 boards of commerce may beused as the core for my new board. A well known board of this'typehaving good insulating properties is known as Temlok and is made ofloosely associated, fi-.

bratcd wood chips, preferably, the refuse pine 5 5 chips from rosinextraction plants, bonded by a resin size into a low density board. Thismaterial and the process of its manufacture is disclosed irTSmith,Pieper and Vogt Patent No. 1,873,056 issued August 23, 1932. The boardhas sufficient structural strength to permit handling in installation,and is relatively low in density, high in insulating value and presentsa fibrous surface which is somewhat rough in appearance.

A typical insulation board of the fibrous type would have I Weight, 1.45pounds per square foot one inch thick; conductivity of (Koo) .34 B. t.u. per hour per degree temperature change per inch of thickness; modulusof rupture of approximately 450 pounds per square inch; a deflection of.05 inch when tested in accordance with Federal specifications for fiberboard which includes placing 4 x 12 inch sample on parallel supports inradius and 8" apart with a load of 10 pounds applied at midspan througha rod in radius for 30 seconds with a deflection at the center measuredby means of adial gauge; water absorption equivalent to 3.5% by volumeof the original sample when immersed in water for 2 hours andapproximately 2 per cent of linear expansion due to such waterabsorption. The density of the core for use in my board may be muchlower than would be practicable in an ordinary fibrous insulation boardwithout a sheathing.

"Temlok" is considerably more water resistant than many fibrousinsulation boards due to the water resistant nature of the rosin in thechips which rosin coats the chips and serves in combination as a binder.Boards made from paper pulp, for example, and which would be suitablefor use as a core in my insulation board would have considerably higherwater absorption and consequently expansion would be greater.

In order to render the core fire resistant and further to preventexpansion upon the absorption of moisture, I provide a layer ofhydraulic setting cementitious material to the exposed faces of the coreand preferably also to the longitudinal edges, which material is set insitu on the board thereby forming a mechanical bond therewith. Due tothe open fibrous character of the core, the composition which is in aplastic state flows around the intertwined surface fibers and isinterlocked firmly therewith upon setting, forming a so-calledmechanical bond with the fibers of the board. There is also an adhesivebond by virtue of the cementitious material adhering to the surface ofthe fibers. The thickness of the layer may vary considerably and may beof non-uniform thickness on the faces and/or edges. I prefer to apply alayer about 9;" thick to the faces of the core although a highlydesirable .board may be produced in which one face, for example,- theface to be exposed, may have a layer V," thick and the inner face alayer thick. It is desirable to apply sufilcient cementitious materialto build up a smooth surface on the board, but the thickness mayvarywithin wide It has been found that the usual gypsum mix may be used tosheath the core. A typical mix of this sort is as follows:

. Parts by weight Gypsum 100 Water 65 Any hydraulic setting cementitiousmaterial the following' characteristics:

protective by the pressure applied such as hydraulic cement which willimpart rigidity to the board and will prevent expansion upon theabsorption of water will be satisfactory as a substitute for the gypsumdisclosed. In order to increase the rigidity and structural strength ofthe board and at the same time provide an improved surface fordecoration, I prefer to secure to the gypsum layers cover sheets ofpaper or other. membranes which may be waterproofed if desired. From theabove description it will be seen that my invention contemplates aninsulation board core having applied to the opposed faces thereof, andset in situ thereon, a layer of hydraulic setting cementitiouscomposition, and if desired paper or similar cover sheets securedthereto, and preferably held by the cementitious composition.

In order that my invention may be more readily understood I willdescribe the same in connection with the accompanying drawing in whichFigure 1 is a diagrammatic view of suitable mechanism to carry out theprocess of my invention;

Figure 2.is a plan view partially broken away illustrating my newinsulation board;

Figure 3is a sectional view taken on the line lII-I1I of Figure 2;

Figure 4 is a plan view partially broken away illustrating a preferredtype of core joint;

Figures 5 and 6 are plan views illustrating other core joints;

Figure 7 is a sectional view of a modified construction; and

Figure 8 is a sectional view of a further modificationi v The mechanismused in carrying out my invention may be in the form of a modifiedgypsum board machine as diagrammatically shown in Figure 1. According tomy preferred procedure, a lower cover sheet 2 is fed from a roll 3 overa supporting table 4 where a layer of hydraulic setting cementitiouscomposition 5, such as gypsum, is applied thereto from a mass 6 placedon 'thesheet 2 in the path of a core 1 which is shown in the form of aweb of fibrous insulation material. The sheet'! may be chip board and ispreferably wider than the final desired width of the finished productand is folded so as to cover the longitudinal edges of the board. Ifdesired, the sheet 2 may be first scored at the lines 8 and 9 (Figure 3)to facilitate folding. Rotating grinding wheels ll backed'by a roll ll(Figure 1) which are conventional elements in gypsum board machines maybe used. The longitudinal edges of thelower cover sheet 2 are urged intoa vertical position as indicated at I! and serve to confine the gypsumwhich is squeezed out upon application of pressure to the core I by apressure roll II. By adjusting the position of the roll I l with respectto the table 4, the thickness of the layer 5 may be varied since thelayer 5 is spread to the core 1 in its forward movement acting againstthe mass 0 which is also being urged forwardly by movement of a conveyorI4 carrying the cover sheet 2. It is preferred to feed the core materialas a continuous web from the drying ovens employed in the manufacture offiber boards of this type for by user! a continuous web of insulationthe problems incident to joining the boards are obviated.

The board or web 1 is supported on rollers i I to facilitate feeding andto permit the application of water, if desired, to the under side of theboard. When a relatively thin layer of gypsum s used as the cementitiouslayer, it has been found desirable to moisten the board so as to preventtoo rapid egress of moisture from the composition into the board wherebythe bond is weakened and cracking often results. The water may beapplied to the board by spray nozzles i6 attached to a suitable sourceof water supply. Spray booths I! are employed to confine the spray, andthe lower booth is preferably provided with a suitable drain ii to carryaway any excess water. It will be understood that certain cementitiouscompositions will not require premoistening of the surface and othercompositions while requiring such moistening when employed in relativelythin layers will not require it if relatively thicker layers areapplied.

The moistened sheet is fed'forwardly with the lower cover sheet and alayer of cementitious composition l3 preferably similar-to thecomposition 5 is applied to the exposed face of the core I from a massin a manner similar to the application of the layer 5. The verticallyextending edges l2 of the lower cover sheet 2 are urged inwardly anddownwardly by the guide 2| into the mass of gypsum 20 whereby a portionof the mass is applied to the top as well as to the under side of theinturned portion as is clearly illustrated in Figure 3 and the plasticcomposition 5' squeezed out upon the application of pressure to the coreI is urged into engagement with the longitudinal edges of the core. Thescoring 9 permits ready bending of the sheet 2 by the guide 2|.

It.will be noted by reference to Figure 3 that the lower cover sheet 2encloses the under face as well as the longitudinal edges and a portionof the top face of the board and the edges l2 are embedded in theplastic composition IS with the composition covering the portions 22 ofthe upper surfaces thereof and serving to secure the upper cover sheet23 which is next applied.

Referring again to Figure l, the cover sheet 23 which may be similar tothe cover sheet 2 is fed from a roll 24 and the longitudinal edgesthereof may be 'skived as at 25 (Figure 3)'"by means of grinding wheels26 mounted for operation on the opposite longitudinal edges of the coversheet and backed by a roll 21. By skiving these edges as shown, arelatively smooth upper surface is provided, which prevents the edgesfrom being scuffed loose during transportation and handling. If desiredthe sheet 23 may be secured in position over the inturned edges l2 ofthe under cover sheet by.means of a suitable adhesive applied adjacentthe line of contact between the sheets. In practice it has been foundthat the gypsum which covers the portions 22 of the inturned edges l2 ofthe lower cover sheet 2 provides a satisfactory bond for the outer coversheet, however. In

order to further prevent disengagement of the two sheets in shipment andhandling the upper the width of the final board and provides marginalportions 23 on the opposite longitudinal edges of the board formed bythe inturned lower cover sheet.

Various types of edge construction may be em ployed as desired. Forexample, the upper cover sheet may be folded to cover the longitudinaledges of the board in combination with the lower engagement with anoscillating smoothing plate 3| and cut into the 'desired lengths fordrying by means of a flying guillotine knife 32 or other suitablecutting mechanism. The material then passes into a suitable drying ovenand the cementitious composition is hydraulically set in situ on theflbersof the insulation board, whereby a mechanical asuwell as anadhesive bond is obtained. e

In some instances it may be found desirable to form the core layer I ofa plurality of individual pieces. It will be necessary when suchprocedure is carried out to carefully manipulate the material in theforming operation in order to obviate bulges at the line of juncturebetween the adjacent pieces of insulating board. The sheets may be cutat with respect to the longitudinal edges of the board, but I prefer tocut the material on a bias as illustrated in Figure 4 in which thepieces have the form of a parallelepipedon with included angles of and60 on the large faces thereof. Other shapes may be employed if desired.When the sheet is cut to the desired size from the continuous lengththus formed, the line of cutting being indicated by the dotted line 33,there will be no tendency for the portion 34 formed by the smallremaining piece of insulation board to become broken away from the mainbody of the board which might'be the case if joints extending at anangle 90 to the longituify the apparatus to feed these pieces in thedesired manner.

If desired, the core may be formed of pieces with longitudinal andtransverse joints as illustrated in Figure 5. The transverse joints arepreferably staggered as illustrated at 35 and 36 in order that therewill be no weakened portion transversely of the entire width of theboard.

The number of pieces required for a given width may be varied asdesired. In Figure 5 each piece is equivalent to one-half of the desiredwidth.

In Figureii a still further modification of joint construction isillustrated in which one transverse edge has a salient angle 31 and theother edge has a reentrant angle 38 whereby adjacent pieces interengage.By this construction it is possible to. accurately center the coreportions.

one with respect to the other because the salient angular portion 31terminates in a point which is guided into position by the reentrantportion 38, whereby transverse movement of the core member iscontrolled. .As stated above, various modifications may be employed inthe joint construction. The desired end is to provide a jointconstruction which will not form a bulge on the exterior of the finishedboard and also. to

' provide a board which when cut adjacent a joint will not leave asmall'portion which. is not securely attached to the remainder of theboard.

In the previousembodiments described, the longitudinal edges as well asthe faces of the board have been sheathed in a cementitious compositionand covered with paper. It will be understood that my invention is notso limited but also contemplates a fibrous core having applied to theopposite faces only a layer of hydraulic setting cementitiouscomposition which is mechanically and adhesively secured to the boardand cover sheets applied to the composition, and as illustrated inFigure 7, the core I may be provided with square cut edges free ofgypsum and paper coverings. This type of board has beenfound highlydesirable for certain uses and expansion upon absorption of moisture isnegligible.

It will-be further evident from an examination of Figure 8 that thefibrous core I may be provided with layers of gypsum 5 and I9 and papercover sheets 2 and 23 as in the otherembodiments and a rabbet I! and acorresponding tongue 40 formed therein and adapted for interengagementto form a tight joint. This board is also shown with recesses ll and 42in the form of shallow grooves which serve to hold plaster which may besubsequently applied thereto. In

other words, the embodiment of Figure 8 isa form of insulation lathwhich may conveniently be made from my insulation board.

To compare the product of my invention with the typical example offibrous insulation material previously described herein, a board of myinvention having a core of fibrous insulation with a density of 1.1pounds, layers of gypsum and chip board cover sheets, has the followingcharacteristics: Weight 2.36 pounds per square foot one inch thick;conductivity of (Koo) .37 B. t. u. per hour per degree temperaturechange per inch of thickness; modulus of rupture of approximately 900pounds per square inch; a denection of .01 inch when tested inaccordance with the Federal specifications, described in connection withthe fiber board; water absorption equivalent to 16 per cent by volumeand linear expansion upon such water absorption of not more than onetenth of one per cent; onmany tests no measurable expansion was had.From this it will be seen by comparison with the physicalcharacteristics outlined for fiber board that while the weight per boardfoot has increased slightly, the conductivity is substantially the same,the modulus of rupture has been doubled even though the density of thecore is considerably lower. the defiection is one-fifth of that of fiberboard, the water absorption, while higher due to the addition of waterabsorbing paper cover sheets. has not caused any appreciable linearexpansion in the board, and water absorption from the faces which formthe major surface area of the board has been eliminated. The chipboardabsorbs considerable moisture upon immersion, and for certain useswaterproof cover sheets may be desirable, such for example as asphaltimpregnated felt sheets.

The layers of hydraulic setting cementitious composition applied to thecore are probably responsible for preventing shrinkage and the confiningaction is undoubtedly greatly enhanced by reason of the mechanical bondobtained by the interlocking of the fibers of the board with thecomposition upon setting. I do not wish to be limited by the theory thusexpressed, but, in any event, the board a the unusual property of notexpanding upon the absorption of relatively large amounts of moisture.

While my board is slightly more expensive to manufacturer than thefibrous insulation boards now on themarket, the physical characteristicsimparted by my treatment and present in my product open a new channel ofuse for insulation wall boards not heretofore available because of theinherent deficiencies of the fibrous insulation boards and gypsum wallboards of commerce.

While I have described and illustrated the preferred embodiment of myinvention, it will be understood that the invention is not so limitedbut may be otherwise embodied within of the following claims.

1. An insulation board comprising a core of fibrous insulation boardhaving open porous faces and susceptible to expansion uponabsorption ofmoisture, layers of gypsum formed in situ onthe faces thereof andreenforcing cover sheets bonded to said gypsum layers upon settingthereof; said gypsum layers restricting expansion of said core upon theabsorption of moisture.

2. An insulation board comprising a core of fibrous insulation board,susceptible to expansion upon absorption of moisture, relatively thinlayers of hydraulic setting, fire resistant cementitious material formedin situ on the faces of said core, mechanically and adhesively securedthereto and restricting expansion of said core upon absorption ofmoisture, and cover sheets bonded thescope to the layers of cementitiousmaterial upon setting thereof.

3. An insulation board comprising a core of fibrous insulation board,susceptible to expansion upon absorption of moisture, relatively thinlayers of gypsum formed in situ on the faces thereof, and reenforcingpaper sheets bonded to said gypsum layers upon setting thereof, saidgypsum layers restricting expansion of said core upon the absorption ofmoisture.

4. An insulation board comprising a core of structural heat insulationboard of an open. porous character capable of absorbing and holdingmoisture and susceptible to expansion upon such absorption, a casing inthe form of a relatively thin layer of gypsum applied to the faces andlongitudinal edges of the core and set thereon, and reenforcing coversheets applied to said gypsum and secured thereto by setting of saidgypsum, said gypsum stiffening said core and restricting expansion ofsaid core upon the absorption of moisture.

5. An insulation board comprising a core of fibrous, structural heatinsulation board of an open, porous character, susceptible to expansionupon absorption of moisture, a sheathing of gypsum applied to the facesand longitudinal edges of said core and set thereon whereby said core ismechanically and adhesively held in position, and reenforcing coversheets of paper applied to said gypsum and secured thereto upon settingthereof, said sheathing restricting expansion of said core upon theabsorption of moisure.

6. An insulation board comprising a core formed of a plurality ofstructural, fibrous insulation elements, lying in juxtaposition with twoedges thereof parallel to the length of said board and with theirtransverse edges extending generally at an angle other than with respectto the length of said board, relatively'thin layersof hydraulic setting,fire resistant cementitious material formed in. situ on the faces ofsaid core elements, said layers restricting expension of said elements.upon absorption of moisture, and cover sheets secured to said layersuponsetting thereof andreenforcing the board.

7; An insulation board comprising a core formed of a plurality ofstructural, fibrous insulation elements having transverse andlongitudinal joints, one transverse joint being ofiset longitudinallywith respect to another transverse joint, a sheathing of hydraulicsetting cementitious material formed in situ on said elements, saidlayers restricting expansion of said elements upon absorption ofmoisture, and cover sheets secured to said layers upon setting thereofand reenforcing the board.

8. An insulation board comprising a core of low density, fibrousinsulation board, susceptible to expansion upon absorption of moisture,a sheathing of hydraulic setting cementitious material applied andbonded thereto by setting in situ thereon and asphalt saturated fibrouscover sheets secured to said sheathing upon setting thereof, saidsheathing restricting expansion of said core upon the absorption ofmoisture.

9. As a new article of manufacture, a plaster lath in the form of aboard like element having complementary interengaging means on theiongitudinal edges thereof, and provided with a plaster securing groove,said element comprising a core of fibrous insulation board, susceptibleto expansion upon absorption of moisture, layers of hydraulic settingcementitious material applied to at least the faces thereof and bondedthereto by setting in situ thereon, and paper cover sheets secured tosaid cementitious layer upon setting thereof, said cementitious layersrestricting expansion of said core upon the absorption of moisture andsaid paper sheets reenforcing said cementitious layer. 1

10. In the method of making insulation boards, the steps consisting inadvancing a web of covering material, applying a layer of hydraulicsetting cementitious composition to said web, applying fibrousinsulation board to said composition prior to setting thereof, applyinga layer of hydraulic setting cementitious composition to the exposedface of said insulation, applying a cover sheet to said last-named layerand forming rigid fire resistant composition layers in situ on saidinsulation by setting said hydraulic setting composition.

11. In the method of making insulation boards, the steps consisting inadvancing a web of paper covering material, applying a relatively thinlayer of gypsum to said web, applying fibrous insulation board which hasbeen pre-moistened to said composition prior to setting thereof,applying a relatively thin layer of gypsum to the exposed face of saidinsulation, applying a paper cover sheet to said last-named layer andforming a fire resistant, rigid insulation board by setting saidcomposition layers while in adhesive engagement with the paper coversheets and the insulation board.

12. In the method of making insulation boards, the steps consisting inadvancing a web of covering material having a width greater than thewidth of the final desired product and sufficient to cover one face, thelongitudinal edges and at least a portion of the opposite face of thefinished product, applying mass of hydraulic setting cementitiouscomposition to said web, advancing a web of porous, fibrous, heatinsulation board which is self-sustaining and moisture absorbent intoengagement with said mass, applying pressure to said insulation todistribute said composition over said web in a layer, applying a secondmass of hydraulic setting cementitious composition to the exposed faceof said insulation board, urging the longitudinal edges of said web ofcovering material into said second mass of composition whereby thelongitudinal edges of said web of covering material are embeddedtherein, advancing a cover sheet into engagement with said mass,applying pressure to said cover sheet to distribute said compositionover said insulation in a layer, and forming a rigid, protecting sheathin situ on said insulation by setting said composition layers on saidinsulation.

13. In the method of making insulation boards, the steps consisting inadvancing a sheet of covering material, applying a layer of hydraulicsetting cementitious composition to said web, applying pieces of porous,heat insulation board to said composition prior to setting thereof withthe longitudinal edges of said insulation extending parallel to theedges of said web and the transverse edges extending at an angle otherthan with respect thereto, applying a layer of hydraulic settingcementitious composition to the exposed face of said insulation,applying a sheet of covering material to said last-named layer andsetting said composition layers while in adhesive engagement with saidinsulation and said sheets.

14. In the method of making insulation boards, the steps consisting inadvancing a web of covering material, applying a layer of gypsum to saidweb, applying fibrous insulation board to said composition prior tosetting thereof, applying a layer of gypsum to the exposed face of saidinsulation, applying a cover sheet to said last-named layer, settingsaid gypsum while in adhesive engagement with said insulation and saidcover sheets, and thereafter contouring said board to the desired finalshape.

15. In the method of making rigid fire resistant insulation units, thesteps consisting in advancing a cover sheet, applying a layer ofhydraulic setting cementitious composition to said sheet, applyingmoisture to the faces of a sheet of fibrous, heat insulation material inboard form, urging said sheet in engagement with said composition,applying a layer of hydraulic setting cementitious composition to theexposed face of said insulation, applying a cover sheet to saidlastnamed layer, setting said composition layers while in engagementwith the insulation and the cover sheets and cutting the integralstructure so formed into desired shapes.

16. An insulation board comprising a core formed of a plurality ofstructural, heat insulation elements of self-sustaining character lyingin juxtaposition with two edges thereof parallel to the length of theboard and with their transverse edges extending generally at an angleother than 90 with respect to the length of the board. a relatively thinsheathing of gypsum encasing said boards on the fiat faces andlongitudinal edges at least thereof and restricting expansion of saidelements upon absorption of moisture, and a fibrous membrane coveringsaid gypsum sheathing and reenforcing the same, said gypsum sheathingsecuring the elements as a unit by setting while in contact therewith.

STEPHEN J. KELLEY.

